Integrated Circuit Package and Method

ABSTRACT

In an embodiment, a package includes: a first redistribution structure; a first integrated circuit die connected to the first redistribution structure; a ring-shaped substrate surrounding the first integrated circuit die, the ring-shaped substrate connected to the first redistribution structure, the ring-shaped substrate including a core and conductive vias extending through the core; a encapsulant surrounding the ring-shaped substrate and the first integrated circuit die, the encapsulant extending through the ring-shaped substrate; and a second redistribution structure on the encapsulant, the second redistribution structure connected to the first redistribution structure through the conductive vias of the ring-shaped substrate.

PRIORITY CLAIM AND CROSS-REFERENCE

This application is a divisional of U.S. patent application Ser. No.16/207,850, filed on Dec. 3, 2018, which claims the benefit of U.S.Provisional Application No. 62/737,246, filed on Sep. 27, 2018, whichapplications are hereby incorporated herein by reference.

BACKGROUND

The semiconductor industry has experienced rapid growth due to ongoingimprovements in the integration density of a variety of electroniccomponents (e.g., transistors, diodes, resistors, capacitors, etc.). Forthe most part, improvement in integration density has resulted fromiterative reduction of minimum feature size, which allows morecomponents to be integrated into a given area. As the demand forshrinking electronic devices has grown, a need for smaller and morecreative packaging techniques of semiconductor dies has emerged. Anexample of such packaging systems is Package-on-Package (PoP)technology. In a PoP device, a top semiconductor package is stacked ontop of a bottom semiconductor package to provide a high level ofintegration and component density. PoP technology generally enablesproduction of semiconductor devices with enhanced functionalities andsmall footprints on a printed circuit board (PCB).

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIGS. 1 through 7B are cross-sectional views of intermediate steps of aprocess for forming a ring-shaped substrate, in accordance with someembodiments.

FIGS. 8 through 17 are cross-sectional views of intermediate steps of aprocess for packaging a ring-shaped substrate with other devices to forma package component, in accordance with some embodiments.

FIG. 18 is a cross-sectional view of a package structure, in accordancewith some embodiments.

FIG. 19 is a cross-sectional view of a package structure, in accordancewith some other embodiments.

FIG. 20 is a cross-sectional view of a package structure, in accordancewith some other embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are, of course, merely examples and arenot intended to be limiting. For example, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed between the first and second features, such thatthe first and second features may not be in direct contact. In addition,the present disclosure may repeat reference numerals and/or letters inthe various examples. This repetition is for the purpose of simplicityand clarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

In accordance with some embodiments, a ring-shaped substrate is formedor provided. The ring-shaped substrate includes a substrate core havingconductive lines and vias. A cavity in the ring-shaped substrate mayaccommodate a semiconductor device, such as an integrated circuit die.The ring-shaped substrate may then be packaged, with the packageincluding an integrated circuit die disposed in the cavity. The packageis encapsulated with, e.g., a molding compound. Because the ring-shapedsubstrate is rigid, it provides mechanical support when forming thepackage. By avoiding coefficient of thermal expansion (CTE) mismatchbetween the encapsulant and other components of the package, warpage maybe reduced and overall stacking height of the package may be decreased.

FIGS. 1 through 7B are cross-sectional views of intermediate steps of aprocess for forming a ring-shaped substrate 100, in accordance with someembodiments. Although the formation of one ring-shaped substrate 100 isshown, it should be appreciated that multiple ring-shaped substrates 100may be simultaneously formed using a same wafer or substrate, and may besubsequently singulated to form individual ring-shaped substrates 100.

In FIG. 1, a substrate core 102 having seed layers 104 on opposing sidesis provided. The substrate core 102 may be formed from a pre-impregnatedcomposite fiber (“prepreg”), an insulating film or build-up film, paper,glass fiber, non-woven glass fabric, silicon, or the like. The substratecore 102 is formed from materials that help achieve a CTE match withsilicon. In some embodiments, the substrate core 102 is formed from aprepreg including glass fiber and a resin. The seed layers 104 may beone or more layers of copper, titanium, nickel, aluminum, compositionsthereof, or the like, and are deposited or laminated onto opposing sidesof the substrate core 102. In some embodiments, the substrate core 102and seed layers 104 are a copper-clad epoxy-impregnated glass-clothlaminate, a copper-clad polyimide-impregnated glass-cloth laminate, orthe like.

In FIG. 2, openings 106 are formed in the substrate core 102 and seedlayers 104. In some embodiments, the openings 106 are formed by laserdrilling. Other processes, such as mechanical drilling with a drill bit,may also be used to form the openings 106. The openings 106 may have anytop-view shape, such as a polygon, a circle, or the like. A cleaningprocess may then be performed to clean areas near the openings 106 whichmay have been smeared with removed material of the substrate core 102.The cleaning process may be a desmear process. The desmearing may beaccomplished mechanically (e.g., blasting with a fine abrasive in a wetslurry), chemically (e.g., rinsing with a combination of organicsolvents, permanganates, and the like), or by a combination ofmechanical and chemical processes.

In FIG. 3, conductive vias 108 are formed in the openings 106 andconductive lines 110 are formed on opposite sides the substrate core102. The conductive vias 108 and conductive lines 110 may be formed froma conductive material such as copper, titanium, tungsten, aluminum, orthe like. The conductive vias 108 and conductive lines 110 may be formedfrom the same material or different materials, and may be formed by asame process or different processes. In some embodiments, the conductivevias 108 are formed with a first process and the conductive lines 110are formed with a second process. For example, a first plating process,such as electroless plating, may be used to deposit a conductivematerial in the openings 106, thereby forming the conductive vias 108.In embodiments where electroless plating is used, seed layers may beformed in the openings 106. A second plating process, such aselectroplating, electroless plating, or the like, may be performed usingthe seed layers 104. A photoresist is formed and patterned on the seedlayers 104. The photoresist may be formed by spin coating or the likeand may be exposed to light for patterning. The pattern of thephotoresist corresponds to the conductive lines 110. The patterningforms openings through the photoresist to expose the seed layer. Aconductive material is formed in the openings of the photoresist and onthe exposed portions of the seed layer. The conductive material may beformed by plating, such as electroplating or electroless plating, or thelike. The photoresist and portions of the seed layers 104 on which theconductive material is not formed are removed. The photoresist may beremoved by an acceptable ashing or stripping process, such as using anoxygen plasma or the like. Once the photoresist is removed, exposedportions of the seed layers 104 are removed, such as by using anacceptable etching process, such as by wet or dry etching. The remainingportions of the seed layers 104 and conductive material form theconductive lines 110.

In FIG. 4, solder resist layers 112 are formed over the opposing sidesof the substrate core 102, on the conductive lines 110. The solderresist layers 112 protect areas of the substrate core 102 from externaldamage. In some embodiments, the solder resist layers 112 are formed bydepositing a photosensitive dielectric layer, exposing thephotosensitive material with an optical pattern, and developing theexposed layer to form openings 114. In some embodiments, the solderresist layers 112 are formed by depositing a non-photosensitivedielectric layer (e.g., silicon oxide, or silicon nitride, or the like),and patterning the dielectric layer with acceptable photolithography andetching techniques to form the openings 114. The openings 114 exposeunderlying portions of the conductive lines 110 that may be used asconnector pads in subsequent processes.

In FIG. 5, protection layers 116 are optionally formed in the openings114, on exposed portions of the conductive lines 110. The protectionlayers 116 may each be a single layer or a composite layer including aplurality of layers. The protection layers 116 may be formed from ametal such as nickel, tin, tin-lead, gold, silver, palladium, indium,nickel-palladium-gold, nickel-gold, the like, or a combination thereof.In some embodiments, the protection layers 116 may be Electroless NickelImmersion Gold (ENIG), which includes gold layers on the exposedportions of the conductive lines 110 and nickel layers on the goldlayers. In some embodiments, the protection layers 116 may beElectroless Nickel Electroless Palladium Immersion Gold (ENEPIG), whichincludes gold layers on the exposed portions of the conductive lines110, palladium layers on the gold layers, and nickel layers on thepalladium layers. The protection layers 116 may be formed by electroplating, electroless plating, immersion, physical vapor deposition(PVD), or combinations thereof. The hardness of the protection layers116 may be greater than the hardness of the underlying conductive lines110.

In FIG. 6, conductive connectors 118 are formed in the openings 114. Inembodiments where the protection layers 116 are used, the conductiveconnectors 118 contact the protection layers 116. In embodiments wherethe protection layers 116 are omitted, the conductive connectors 118contact the exposed portions of the conductive lines 110. The conductiveconnectors 118 may be ball grid array (BGA) connectors, solder balls,metal pillars, controlled collapse chip connection (C4) bumps, microbumps, electroless nickel-electroless palladium-immersion gold technique(ENEPIG) formed bumps, or the like. The conductive connectors 118 mayinclude a conductive material such as solder, copper, aluminum, gold,nickel, silver, palladium, tin, the like, or a combination thereof. Insome embodiments, the conductive connectors 118 are solder connectorsthat are formed by initially forming a layer of solder through commonlyused methods such as evaporation, electroplating, printing, soldertransfer, ball placement, or the like. Once a layer of solder has beenformed on the structure, a reflow may be performed in order to shape thematerial into the desired bump shapes. In another embodiment, theconductive connectors 118 comprise metal pillars (such as a copperpillar) formed by a sputtering, printing, electro plating, electrolessplating, chemical vapor deposition (CVD), or the like. The metal pillarsmay be solder free and have substantially vertical sidewalls.

In FIG. 7A, a cavity 120 is formed by removing portions of the substratecore 102 and solder resist layers 112. Removal of material to form thecavity 120 may be accomplished by a mechanical drilling process withcomputer numeric control (CNC). In such embodiments, material is removedby a mechanical drill, with the position of the drill being controlledby a computer or controller. Removal may also be accomplished by otherprocesses, such as a laser cutting process, a laser drilling process, orthe like. Remaining portions of the material form the ring-shapedsubstrate 100.

FIG. 7B is a top-down view of the ring-shaped substrate 100 of FIG. 7A.As can be seen, the ring-shaped substrate 100 has a ring shape in thetop-down view. The cavity 120 extends through a center portion of thering-shaped substrate 100 to form the ring. The example ring-shapedsubstrate 100 in FIG. 7B is rectangular. It should be appreciated thatother embodiments may have other shapes. For example, other ring-shapedsubstrates 100 may be circles, triangles, or the like.

FIGS. 8 through 17 are cross-sectional views of intermediate steps of aprocess for packaging the ring-shaped substrate 100 with other devicesto form a package component 200, in accordance with some embodiments.The package component 200 includes multiple regions, and one ring-shapedsubstrate 100 is packaged in each region. One region of the packagecomponent 200 is illustrated.

In FIG. 8, a carrier substrate 202 is provided, and a release layer 204is formed on the carrier substrate 202. The carrier substrate 202 may bea glass carrier substrate, a ceramic carrier substrate, or the like. Thecarrier substrate 202 may be a wafer, such that multiple packages can beformed on the carrier substrate 202. The release layer 204 may be formedof a polymer-based material, which may be removed along with the carriersubstrate 202 from the overlying structures that will be formed insubsequent steps. In some embodiments, the release layer 204 is anepoxy-based thermal-release material, which loses its adhesive propertywhen heated, such as a light-to-heat-conversion (LTHC) release coating.In other embodiments, the release layer 204 may be an ultra-violet (UV)glue, which loses its adhesive property when exposed to UV lights. Therelease layer 204 may be dispensed as a liquid and cured, may be alaminate film laminated onto the carrier substrate 202, or may be thelike. The top surface of the release layer 204 may be leveled and mayhave a high degree of coplanarity.

In FIG. 9, a first redistribution structure 206 is formed on the releaselayer 204. The first redistribution structure 206 includes dielectriclayers 208, 212, 216, and 220; metallization patterns 210, 214, and 218;and under bump metallurgies (UBMs) 222. The metallization patterns 210,214, and 218 may also be referred to as redistribution layers orredistribution lines. The first redistribution structure 206 is shown asan example. More or fewer dielectric layers and metallization patternsmay be formed in the first redistribution structure 206. If fewerdielectric layers and metallization patterns are to be formed, steps andprocess discussed below may be omitted. If more dielectric layers andmetallization patterns are to be formed, steps and processes discussedbelow may be repeated.

As an example to form the first redistribution structure 206, thedielectric layer 208 is deposited on the release layer 204. In someembodiments, the dielectric layer 208 is formed of a photo-sensitivematerial such as polybenzoxazole (PBO), polyimide, benzocyclobutene(BCB), or the like, which may be patterned using a lithography mask. Thedielectric layer 208 may be formed by spin coating, lamination, CVD, thelike, or a combination thereof. The dielectric layer 208 is thenpatterned. The patterning forms openings exposing portions of therelease layer 204. The patterning may be by an acceptable process, suchas by exposing the dielectric layer 208 to light when the dielectriclayer 208 is a photo-sensitive material or by etching using, forexample, an anisotropic etch. If the dielectric layer 208 is aphoto-sensitive material, the dielectric layer 208 can be developedafter the exposure.

The metallization pattern 210 is then formed. The metallization pattern210 includes conductive lines on and extending along the major surfaceof the dielectric layer 208. The metallization pattern 210 furtherincludes conductive vias extending through the dielectric layer 208. Toform the metallization pattern 210, a seed layer is formed over thedielectric layer 208 and in the openings extending through thedielectric layer 208. In some embodiments, the seed layer is a metallayer, which may be a single layer or a composite layer comprising aplurality of sub-layers formed of different materials. In someembodiments, the seed layer comprises a titanium layer and a copperlayer over the titanium layer. The seed layer may be formed using, forexample, PVD, or the like. A photoresist is then formed and patterned onthe seed layer. The photoresist may be formed by spin coating or thelike and may be exposed to light for patterning. The pattern of thephotoresist corresponds to the metallization pattern 210. The patterningforms openings through the photoresist to expose the seed layer. Aconductive material is then formed in the openings of the photoresistand on the exposed portions of the seed layer. The conductive materialmay be formed by plating, such as electroplating or electroless plating,or the like. The conductive material may comprise a metal, like copper,titanium, tungsten, aluminum, or the like. The combination of theconductive material and underlying portions of the seed layer form themetallization pattern 210. The photoresist and portions of the seedlayer on which the conductive material is not formed are removed. Thephotoresist may be removed by an acceptable ashing or stripping process,such as using an oxygen plasma or the like. Once the photoresist isremoved, exposed portions of the seed layer are removed, such as byusing an acceptable etching process, such as by wet or dry etching.

The dielectric layer 212 is deposited on the metallization pattern 210and dielectric layer 208. The dielectric layer 212 may be formed in amanner similar to the dielectric layer 208, and may be formed of thesame material as the dielectric layer 208.

The metallization pattern 214 is then formed. The metallization pattern214 includes conductive lines on and extending along the major surfaceof the dielectric layer 212. The metallization pattern 214 furtherincludes conductive vias extending through the dielectric layer 212 tobe physically and electrically connected to the metallization pattern210. The metallization pattern 214 may be formed in a manner similar tothe metallization pattern 210, and may be formed of the same material asthe metallization pattern 210. The conductive vias of the metallizationpattern 214 have smaller width than the conductive vias of themetallization pattern 210. As such, when patterning the dielectric layer212 for the metallization pattern 214, the width of the openings in thedielectric layer 212 are smaller than the width of the openings in thedielectric layer 208.

The dielectric layer 216 is deposited on the metallization pattern 214and dielectric layer 212. The dielectric layer 216 may be formed in amanner similar to the dielectric layer 208, and may be formed of thesame material as the dielectric layer 208.

The metallization pattern 218 is then formed. The metallization pattern218 includes conductive lines on and extending along the major surfaceof the dielectric layer 216. The metallization pattern 218 furtherincludes conductive vias extending through the dielectric layer 216 tobe physically and electrically connected to the metallization pattern214. The metallization pattern 218 may be formed in a manner similar tothe metallization pattern 210, and may be formed of the same material asthe metallization pattern 210. The conductive vias of the metallizationpattern 218 have smaller width than the conductive vias of themetallization pattern 210. As such, when patterning the dielectric layer216 for the metallization pattern 218, the width of the openings in thedielectric layer 216 are smaller than the width of the openings in thedielectric layer 208.

The dielectric layer 220 is deposited on the metallization pattern 218and dielectric layer 216. The dielectric layer 220 may be formed in amanner similar to the dielectric layer 208, and may be formed of thesame material as the dielectric layer 208.

The UBMs 222 are formed on and extending through the dielectric layer220. As an example to form the UBMs 222, the dielectric layer 220 may bepatterned to form openings exposing portions of the metallizationpattern 218. The patterning may be by an acceptable process, such as byexposing the dielectric layer 220 to light when the dielectric layer 220is a photo-sensitive material or by etching using, for example, ananisotropic etch. If the dielectric layer 220 is a photo-sensitivematerial, the dielectric layer 220 can be developed after the exposure.The openings for the UBMs 222 may be wider than the openings for theconductive via portions of the metallization patterns 210, 214, and 218.A seed layer is formed over the dielectric layer 220 and in theopenings. In some embodiments, the seed layer is a metal layer, whichmay be a single layer or a composite layer comprising a plurality ofsub-layers formed of different materials. In some embodiments, the seedlayer comprises a titanium layer and a copper layer over the titaniumlayer. The seed layer may be formed using, for example, PVD or the like.A photoresist is then formed and patterned on the seed layer. Thephotoresist may be formed by spin coating or the like and may be exposedto light for patterning. The pattern of the photoresist corresponds tothe UBMs 222. The patterning forms openings through the photoresist toexpose the seed layer. A conductive material is formed in the openingsof the photoresist and on the exposed portions of the seed layer. Theconductive material may be formed by plating, such as electroplating orelectroless plating, or the like. The conductive material may comprise ametal, like copper, titanium, tungsten, aluminum, or the like. Then, thephotoresist and portions of the seed layer on which the conductivematerial is not formed are removed. The photoresist may be removed by anacceptable ashing or stripping process, such as using an oxygen plasmaor the like. Once the photoresist is removed, exposed portions of theseed layer are removed, such as by using an acceptable etching process,such as by wet or dry etching. The remaining portions of the seed layerand conductive material form the UBMs 222. In embodiments where the UBMs222 are formed differently, more photoresist and patterning steps may beutilized.

The UBMs 222 may not all have the same width. In some embodiments, afirst subset of the UBMs 222 in a first region 206A of the firstredistribution structure 206 have a first width W₁, and a second subsetof the UBMs 222 in a second region 206B of the first redistributionstructure 206 have a second width W₂. The first width W₁ may bedifferent from the second width W₂, and in some embodiments the firstwidth W₁ is greater than the second width W₂.

In FIG. 10, the ring-shaped substrate 100 is placed over the firstredistribution structure 206. The ring-shaped substrate 100 may bealigned and placed using, e.g., a pick-and-place tool. The conductiveconnectors 118 of the ring-shaped substrate 100 are aligned with theUBMs 222 in the first region 206A, and the cavity 120 of the ring-shapedsubstrate 100 is aligned over the UBMs 222 in the second region 206B. Inembodiments where the conductive connectors 118 are solder, theconductive connectors 118 may not be immediately reflowed to bond thering-shaped substrate 100 to the UBMs 222. Reflow of the conductiveconnectors 118 may be delayed until a subsequent processing step. Inembodiments where the conductive connectors 118 are copper pillars,solder may be formed, bonding the conductive connectors 118 to the firstredistribution structure 206

In FIG. 11, an integrated circuit die 224 is placed over the firstredistribution structure 206. The integrated circuit die 224 may be alogic die (e.g., central processing unit, microcontroller, etc.), memorydie (e.g., dynamic random access memory (DRAM) die, static random accessmemory (SRAM) die, etc.), power management die (e.g., power managementintegrated circuit (PMIC) die), radio frequency (RF) die, sensor die,micro-electro-mechanical-system (MEMS) die, signal processing die (e.g.,digital signal processing (DSP) die), front-end die (e.g., analogfront-end (AFE) die), the like, or a combination thereof (e.g., asystem-on-chip (SoC)).

The integrated circuit die 224 includes a semiconductor substrate, withdevices such as transistors, diodes, capacitors, resistors, etc., formedin and/or on the semiconductor substrate. The devices may beinterconnected by interconnect structures formed by, for example,metallization patterns in one or more dielectric layers on thesemiconductor substrate to form an integrated circuit. The integratedcircuit die 224 further comprises pads 226, such as aluminum pads, towhich external connections are made. The pads 226 are on what may bereferred to as respective active sides of the integrated circuit die224, and may be in uppermost layers of the interconnect structures.Because the active side of the integrated circuit die 224 faces towardthe first redistribution structure 206, the first redistributionstructure 206 may also be referred to as a “front-side redistributionstructure.” Conductive connectors 228 may be formed on the pads 226. Theconductive connectors 228 may be formed from a conductive material suchas solder, copper, aluminum, gold, nickel, silver, palladium, tin, thelike, or a combination thereof. In some embodiments, the conductiveconnectors 228 are solder connectors.

The integrated circuit die 224 may be aligned and placed using, e.g., apick-and-place tool. The integrated circuit die 224 is placed within thecavity 120 such that the conductive connectors 228 are aligned with theUBMs 222 in the second region 206B. After the integrated circuit die 224is placed, the conductive connectors 228 are reflowed to form jointsbetween corresponding UBMs 222 and pads 226, physically and electricallyconnecting the integrated circuit die 224 to the first redistributionstructure 206. In embodiments where the conductive connectors 118 of thering-shaped substrate 100 are solder and reflow is delayed, theconductive connectors 118 and 228 may be simultaneously reflowed in thesame reflow process. As such, the conductive connectors 118 may also bereflowed to form joints between corresponding UBMs 222 and conductivelines 110, physically and electrically connecting the ring-shapedsubstrate 100 to the first redistribution structure 206. In other words,the integrated circuit die 224 and ring-shaped substrate 100 may besimultaneously bonded to the first redistribution structure 206. Theconductive connectors 118 and 228 may be different size. In someembodiment, a height H₁ of the ring-shaped substrate 100 is less than orequal to a height H₂ of the integrated circuit die 224. The height H₁may also be greater than the height H₂. Further, the width of theintegrated circuit die 224 is less than the width of the cavity 120.

It should be appreciated that the integrated circuit die 224 andring-shaped substrate 100 may be placed over the first redistributionstructure 206 in any order. In some embodiments, the integrated circuitdie 224 is placed first, and the ring-shaped substrate 100 is placedaround the integrated circuit die 224.

In FIG. 12, an underfill 230 may be formed between the integratedcircuit die 224 and first redistribution structure 206, surrounding theconductive connectors 228. As such, the conductive connectors 228 may beprotected from mechanical forces. The underfill 230 may be formed by acapillary flow process after the integrated circuit die 224 is attached,or may be formed by a suitable deposition method before the integratedcircuit die 224 is attached.

In FIG. 13, an encapsulant 232 is formed on the various components. Theencapsulant 232 may be a molding compound, epoxy, or the like, and maybe applied by compression molding, transfer molding, or the like. Theencapsulant 232 may be formed over the first redistribution structure206 such that the integrated circuit die 224 and ring-shaped substrate100 are buried or covered and the cavity 120 is filled. Portions of theencapsulant 232 burying the ring-shaped substrate 100 have a thicknessT₁. In some embodiments, the thickness T₁ is in the range of from about10 μm to about 100 μm. The encapsulant 232 is then cured, and mayoptionally be planarized by, e.g., a grinding or chemical-mechanicalpolish (CMP) process. After formation, the encapsulant 232 has a heightH₃, which is greater than the heights H₁ and H₂. The encapsulant 232 isalso formed between the first redistribution structure 206 and theintegrated circuit die 224, for example, in embodiments where theunderfill 230 is omitted.

The ring-shaped substrate 100 occupies a significant portion of thevertical height of the package component 200, and so the amount ofencapsulant 232 needed to cover the integrated circuit die 224 may bereduced. For example, a ratio of the height H₃ to the height H₁ may befrom about 1:0.14 to about 1:0.60. The overall height of the packagecomponent 200 may thus be increased without significantly increasing theamount of encapsulant 232 used. Reducing the amount of encapsulant 232used may help avoid package warpage caused by CTE mismatch between theencapsulant 232 and other components of the package component 200.

In FIG. 14, openings 234 are formed in the encapsulant 232 exposing theprotection layers 116 of the ring-shaped substrate 100. The openings 234may be formed by a drilling process such as laser drilling, mechanicaldrilling, or the like. The openings 234 may have a tapered profile, withan upper width W₃, and a lower width W₄ that is less than or equal tothe upper width W₃. In some embodiments, the upper width W₃ is in therange of from about 50 μm to about 350 μm, and the lower width W₄ is inthe range of from about 50 μm to about 200 μm.

In FIG. 15, conductive connectors 236 are formed in the openings 234.The conductive connectors 236 may be formed from a metal such as solder,copper, aluminum, gold, nickel, silver, palladium, tin, the like, or acombination thereof. In some embodiments, the conductive connectors 236are formed from a paste such as copper paste, solder paste, silverpaste, or the like, and are dispensed by a printing process or the like.In embodiments where a printing process is used, an image with thedesired pattern of the conductive connectors 236 is printed on theencapsulant 232 and in the openings 234 using a stencil. Afterformation, the conductive paste is cured to harden it, thereby formingthe conductive connectors 236. The conductive paste may be cured by anannealing process performed at a temperature of about 80° C. to about230° C., and for a time of from about 20 minutes to about 4 hours. Inembodiments where the conductive connectors 236 are a paste, theconductive connectors 236 may overfill the openings such that they havevia portions extending through the encapsulant 232, and upper portionsextending along the top surface of the encapsulant 232.

In FIG. 16, a second redistribution structure 238 is formed over theconductive connectors 236 and encapsulant 232. Because the active sideof the integrated circuit die 224 faces away from the secondredistribution structure 238, the second redistribution structure 238may also be referred to as a “back-side redistribution structure.” Thesecond redistribution structure 238 includes dielectric layers 240, 244,248, and 252; metallization patterns 242, 246, and 250; and UBMs 254.The metallization patterns may also be referred to as redistributionlayers or redistribution lines. The second redistribution structure 238is shown as an example. More or fewer dielectric layers andmetallization patterns may be formed in the second redistributionstructure 238. If fewer dielectric layers and metallization patterns areto be formed, steps and process discussed below may be omitted. If moredielectric layers and metallization patterns are to be formed, steps andprocesses discussed below may be repeated.

As an example to form the second redistribution structure 238, thedielectric layer 240 is deposited on the conductive connectors 236 andencapsulant 232. In some embodiments, the dielectric layer 240 is formedof a photo-sensitive material such as PBO, polyimide, BCB, or the like,which may be patterned using a lithography mask. The dielectric layer240 may be formed by spin coating, lamination, CVD, the like, or acombination thereof. The dielectric layer 240 is then patterned. Thepatterning forms openings exposing portions of the conductive connectors236. The patterning may be by an acceptable process, such as by exposingthe dielectric layer 240 to light when the dielectric layer 240 is aphoto-sensitive material or by etching using, for example, ananisotropic etch. If the dielectric layer 240 is a photo-sensitivematerial, the dielectric layer 240 can be developed after the exposure.

In embodiments where the conductive connectors 236 overfill theopenings, the dielectric layer 240 may be used as a planarization resetlayer. Notably, the dielectric layer 240 may be formed to a greaterthickness than typical for the bottom dielectric layer of aredistribution structure to allow for planarization. After formation,the dielectric layer 240 may have a thickness T₂ in the range of fromabout 5 μm to about 15 μm. In some embodiments, a post-formationplanarization process is performed. The planarization process mayinclude performing a grinding process or a CMP process on the dielectric240. By using the dielectric layer 240 as a planarization reset layer,the top surface of the dielectric layer 240 may be substantially planar,and may have a higher degree of planarity than the bottom surface(s) ofthe dielectric layer 240. After planarization, the thickness of thedielectric layer 240 may be decreased. The thickness of the dielectriclayer 240 (e.g., the bottom dielectric layer) is thicker than otherdielectric layers of the second redistribution structure 238, such asthe dielectric layer 252 (e.g., the top dielectric layer).

The metallization pattern 242 is then formed. The metallization pattern242 includes conductive lines on and extending along the major surfaceof the dielectric layer 240. The metallization pattern 242 furtherincludes conductive vias extending through the dielectric layer 240 tobe physically and electrically connected to the conductive connectors236. To form the metallization pattern 242, a seed layer is formed overthe dielectric layer 240 and in the openings extending through thedielectric layer 240. In some embodiments, the seed layer is a metallayer, which may be a single layer or a composite layer comprising aplurality of sub-layers formed of different materials. In someembodiments, the seed layer comprises a titanium layer and a copperlayer over the titanium layer. The seed layer may be formed using, forexample, PVD or the like. A photoresist is then formed and patterned onthe seed layer. The photoresist may be formed by spin coating or thelike and may be exposed to light for patterning. The pattern of thephotoresist corresponds to the metallization pattern 242. The patterningforms openings through the photoresist to expose the seed layer. Aconductive material is then formed in the openings of the photoresistand on the exposed portions of the seed layer. The conductive materialmay be formed by plating, such as electroplating or electroless plating,or the like. The conductive material may comprise a metal, like copper,titanium, tungsten, aluminum, or the like. The combination of theconductive material and underlying portions of the seed layer form themetallization pattern 242. The photoresist and portions of the seedlayer on which the conductive material is not formed are removed. Thephotoresist may be removed by an acceptable ashing or stripping process,such as using an oxygen plasma or the like. Once the photoresist isremoved, exposed portions of the seed layer are removed, such as byusing an acceptable etching process, such as by wet or dry etching.

The dielectric layer 244 is deposited on the metallization pattern 242and dielectric layer 240. The dielectric layer 244 may be formed in amanner similar to the dielectric layer 240, and may be formed of thesame material as the dielectric layer 240.

The metallization pattern 246 is then formed. The metallization pattern246 includes conductive lines on and extending along the major surfaceof the dielectric layer 244. The metallization pattern 246 furtherincludes conductive vias extending through the dielectric layer 244 tobe physically and electrically connected to the metallization pattern242. The metallization pattern 246 may be formed in a manner similar tothe metallization pattern 242, and may be formed of the same material asthe metallization pattern 242.

The dielectric layer 248 is deposited on the metallization pattern 246and dielectric layer 244. The dielectric layer 248 may be formed in amanner similar to the dielectric layer 240, and may be formed of thesame material as the dielectric layer 240.

The metallization pattern 250 is then formed. The metallization pattern250 includes conductive lines on and extending along the major surfaceof the dielectric layer 248. The metallization pattern 250 furtherincludes conductive vias extending through the dielectric layer 248 tobe physically and electrically connected to the metallization pattern246. The metallization pattern 250 may be formed in a manner similar tothe metallization pattern 242, and may be formed of the same material asthe metallization pattern 242.

The dielectric layer 252 is deposited on the metallization pattern 250and dielectric layer 248. The dielectric layer 252 may be formed in amanner similar to the dielectric layer 240, and may be formed of thesame material as the dielectric layer 240.

The UBMs 254 are formed on and extending through the dielectric layer252. As an example to form the UBMs 254, the dielectric layer 252 may bepatterned to form openings exposing portions of the metallizationpattern 250. The patterning may be by an acceptable process, such as byexposing the dielectric layer 252 to light when the dielectric layer 252is a photo-sensitive material or by etching using, for example, ananisotropic etch. If the dielectric layer 252 is a photo-sensitivematerial, the dielectric layer 252 can be developed after the exposure.The openings for the UBMs 254 may be wider than the openings for theconductive via portions of the metallization patterns 242, 246, and 250.A seed layer is formed over the dielectric layer 252 and in theopenings. In some embodiments, the seed layer is a metal layer, whichmay be a single layer or a composite layer comprising a plurality ofsub-layers formed of different materials. In some embodiments, the seedlayer comprises a titanium layer and a copper layer over the titaniumlayer. The seed layer may be formed using, for example, PVD or the like.A photoresist is then formed and patterned on the seed layer. Thephotoresist may be formed by spin coating or the like and may be exposedto light for patterning. The pattern of the photoresist corresponds tothe UBMs 254. The patterning forms openings through the photoresist toexpose the seed layer. A conductive material is formed in the openingsof the photoresist and on the exposed portions of the seed layer. Theconductive material may be formed by plating, such as electroplating orelectroless plating, or the like. The conductive material may comprise ametal, like copper, titanium, tungsten, aluminum, or the like. Then, thephotoresist and portions of the seed layer on which the conductivematerial is not formed are removed. The photoresist may be removed by anacceptable ashing or stripping process, such as using an oxygen plasmaor the like. Once the photoresist is removed, exposed portions of theseed layer are removed, such as by using an acceptable etching process,such as by wet or dry etching. The remaining portions of the seed layerand conductive material form the UBMs 254. In embodiments where the UBMs254 are formed differently, more photoresist and patterning steps may beutilized.

After formation, the ring-shaped substrate 100 electrically connects thevarious features of the package component 200. In particular, thering-shaped substrate 100, conductive connectors 118, and conductiveconnectors 236 electrically and physically connect the firstredistribution structure 206 to the second redistribution structure 238.The integrated circuit die 224 is thus electrically connected to thesecond redistribution structure 238 through the first redistributionstructure 206 and the ring-shaped substrate 100.

In FIG. 17, a carrier substrate de-bonding is performed to detach (or“de-bond”) the carrier substrate 202 from the first redistributionstructure 206, e.g., the dielectric layer 208. In some embodiments, thede-bonding includes projecting a light such as a laser light or an UVlight on the release layer 204 so that the release layer 204 decomposesunder the heat of the light and the carrier substrate 202 can beremoved. The structure is then flipped over and placed on a tape. Thede-bonding exposes the metallization patterns 210 of the firstredistribution structure 206.

FIG. 18 is a cross-sectional view of a package structure 300, inaccordance with some embodiments. The package structure 300 includes afirst package 302, integrated circuit dies 304, and a package substrate306. The package structure 300 may be referred to as a side-by-sidemulti-chip-module (SBS-MCM).

The first package 302 is one of the packages formed in the packagecomponent 200. A singulation process is performed on the packagecomponent 200 by sawing along scribe line regions, e.g., between theadjacent package regions of the package component 200. The resultingsingulated first packages 302 are from one of the singulated packageregions.

The integrated circuit dies 304 may be dies that communicate with theintegrated circuit die 224 to form a complete system. For example, inembodiments where the integrated circuit die 224 is a logic die, theintegrated circuit dies 304 may be memory dies, RF dies, passivedevices, or combinations thereof. The integrated circuit dies 304include a semiconductor substrate, with devices such as transistors,diodes, capacitors, resistors, etc., formed in and/or on thesemiconductor substrate. The devices may be interconnected byinterconnect structures formed by, for example, metallization patternsin one or more dielectric layers on the semiconductor substrate to forman integrated circuit. The integrated circuit dies 304 further comprisespads 308, such as aluminum pads, to which external connections are made.The pads 308 are on what may be referred to as respective active sidesof the integrated circuit dies 304, and may be in uppermost layers ofthe interconnect structures. Conductive connectors 310 may be formed onthe pads 308. The conductive connectors 310 may be formed from aconductive material such as solder, copper, aluminum, gold, nickel,silver, palladium, tin, the like, or a combination thereof. Theintegrated circuit dies 304 are mounted to the UBMs 254 using theconductive connectors 310. In some embodiments, the conductiveconnectors 310 are reflowed to attach the integrated circuit dies 304 tothe UBMs 254. In some embodiments, an underfill or encapsulant is formedto fill the gap between the integrated circuit dies 304 and the secondredistribution structure 238. Because the amount of encapsulant 232 usedis reduced, the thickness of the first package 302 may be reduced, whichmay allow integrated circuit dies 304 of greater thickness to beattached. For example, when the integrated circuit dies 304 are memorydevices, the capacity of the memory devices may be increased.

The first package 302 is then mounted to a package substrate 306 usingconductive connectors 312. The package substrate 306 may be made of asemiconductor material such as silicon, germanium, diamond, or the like.Alternatively, compound materials such as silicon germanium, siliconcarbide, gallium arsenic, indium arsenide, indium phosphide, silicongermanium carbide, gallium arsenic phosphide, gallium indium phosphide,combinations of these, and the like, may also be used. Additionally, thepackage substrate 306 may be a silicon-on-insulator (SOI) substrate.Generally, an SOI substrate includes a layer of a semiconductor materialsuch as epitaxial silicon, germanium, silicon germanium, SOI,silicon-germanium-on-insulator (SGOI), or combinations thereof. Thepackage substrate 306 is, in one alternative embodiment, based on aninsulating core such as a fiberglass reinforced resin core. One examplecore material is fiberglass resin such as FR4. Alternatives for the corematerial include bismaleimide-triazine (BT) resin, or alternatively,other PCB materials or films. Build-up films such as Ajinomoto Build-upfilm (ABF) or other laminates may be used for package substrate 306.

The package substrate 306 may include active and passive devices (notshown). As one of ordinary skill in the art will recognize, a widevariety of devices such as transistors, capacitors, resistors,combinations of these, and the like may be used to generate thestructural and functional requirements of the design for the packagestructure 300. The devices may be formed using any suitable methods.

The package substrate 306 may also include metallization layers and vias(not shown) and bond pads 314 over the metallization layers and vias.The metallization layers may be formed over the active and passivedevices and are designed to connect the various devices to formfunctional circuitry. The metallization layers may be formed ofalternating layers of dielectric (e.g., low-k dielectric material) andconductive material (e.g., copper) with vias interconnecting the layersof conductive material and may be formed through any suitable process(such as deposition, damascene, dual damascene, or the like). In someembodiments, the package substrate 306 is substantially free of activeand passive devices.

The conductive connectors 312 may be formed from a conductive materialsuch as solder, copper, aluminum, gold, nickel, silver, palladium, tin,the like, or a combination thereof. In some embodiments, the conductiveconnectors 312 are reflowed to attach the first package 302 to the bondpads 314. The conductive connectors 312 electrically and/or physicallycouple the package substrate 306, including metallization layers in thepackage substrate 306, to the metallization patterns 210 of the firstpackage 302. In some embodiments, passive devices (e.g., surface mountdevices (SMDs), not illustrated) may be attached to the first package302 (e.g., bonded to the bond pads 314) prior to mounting on the packagesubstrate 306. In such embodiments, the passive devices may be bonded toa same surface of the first package 302 as the conductive connectors312.

The conductive connectors 312 may have an epoxy flux (not shown) formedthereon before they are reflowed with at least some of the epoxy portionof the epoxy flux remaining after the first package 302 is attached tothe package substrate 306. This remaining epoxy portion may act as anunderfill to reduce stress and protect the joints resulting from thereflowing the conductive connectors 312. In some embodiments, anunderfill (not shown) may be formed between the first package 302 andthe package substrate 306 and surrounding the conductive connectors 312.The underfill may be formed by a capillary flow process after the firstpackage 302 is attached or may be formed by a suitable deposition methodbefore the first package 302 is attached.

FIG. 19 is a cross-sectional view of the package structure 300, inaccordance with some other embodiments. In the embodiment shown, theunderfill 230 is also formed to surround a subset of the conductiveconnectors 118. As such, some of the conductive connectors 118 may beprotected from mechanical forces.

FIG. 20 is a cross-sectional view of the package structure 300, inaccordance with some other embodiments. In the embodiment shown, theunderfill 230 is also formed to surround all of the conductiveconnectors 118. As such, all of the conductive connectors 118 may beprotected from mechanical forces.

Embodiments may achieve advantages. The ring-shaped substrate 100 isrigid. Using the ring-shaped substrate 100 containing conductive vias108 may increase the vertical support of the package component 200, ascompared to directly forming conductive vias on the first redistributionstructure 206. Further, by soldering the ring-shaped substrate 100 tothe first redistribution structure 206, delamination of conductive viasfrom the first redistribution structure 206 may be avoided.

In an embodiment, a package includes: a first redistribution structure;a first integrated circuit die connected to the first redistributionstructure; a ring-shaped substrate surrounding the first integratedcircuit die, the ring-shaped substrate connected to the firstredistribution structure, the ring-shaped substrate including a core andconductive vias extending through the core; a encapsulant surroundingthe ring-shaped substrate and the first integrated circuit die, theencapsulant extending through the ring-shaped substrate; and a secondredistribution structure on the encapsulant, the second redistributionstructure connected to the first redistribution structure through theconductive vias of the ring-shaped substrate.

In some embodiments, the package further includes: first conductiveconnectors extending through a first portion of the encapsulant, thefirst conductive connectors connecting the first integrated circuit dieto the first redistribution structure; and second conductive connectorsextending through a second portion of the encapsulant, the secondconductive connectors connecting the ring-shaped substrate to the firstredistribution structure, the second conductive connectors being adifferent size than the first conductive connectors. In someembodiments, the package further includes: an underfill disposed betweenthe first integrated circuit die and the first redistribution structure,the underfill surrounding the first conductive connectors. In someembodiments of the package, the underfill further surrounds a firstsubset of the second conductive connectors without surrounding a secondsubset of the second conductive connectors. In some embodiments of thepackage, the underfill further surrounds all of the second conductiveconnectors. In some embodiments of the package, the first conductiveconnectors and the second conductive connectors include copper pillars.In some embodiments of the package, the first conductive connectors andthe second conductive connectors include solder connectors. In someembodiments, the package further includes: third conductive connectorsextending through a third portion of the encapsulant, the thirdconductive connectors connecting the ring-shaped substrate to the secondredistribution structure. In some embodiments of the package, the thirdconductive connectors include conductive paste. In some embodiments ofthe package, the second redistribution structure includes a bottomdielectric layer and a top dielectric layer, the bottom dielectric layercontacting the third conductive connectors and the encapsulant, a topsurface of the bottom dielectric layer having a higher degree ofplanarity than a bottom surface of the bottom dielectric layer, thebottom dielectric layer being thicker than the top dielectric layer. Insome embodiments of the package, the ring-shaped substrate furtherincludes: first conductive lines on a first side of the ring-shapedsubstrate, the first conductive lines connecting the conductive vias tothe first redistribution structure; a first solder resist on the firstconductive lines, the first solder resist surrounding the firstconductive connectors; second conductive lines on a second side of thering-shaped substrate, the second conductive lines connecting theconductive vias to the second redistribution structure; and a secondsolder resist on the second conductive lines, the second solder resistsurrounding the third conductive connectors. In some embodiments of thepackage, a first height of the first integrated circuit die is greaterthan or equal to a second height of the ring-shaped substrate. In someembodiments, the package further includes: a second integrated circuitdie connected to the second redistribution structure; and a packagesubstrate connected to the first redistribution structure. In someembodiments of the package, the core includes a pre-impregnatedcomposite fiber.

In an embodiment, a method includes: patterning first openings in asubstrate; forming conductive vias in the first openings; forming firstconductive connectors connected to the conductive vias, the firstconductive connectors being on a first side of the substrate; patterninga cavity in the substrate; placing the substrate on a firstredistribution structure, the first conductive connectors being coupledto the first redistribution structure; placing an integrated circuit dieon the first redistribution structure and in the cavity of thesubstrate, the integrated circuit die including second conductiveconnectors coupled to the first redistribution structure; encapsulatingthe integrated circuit die and the substrate with an encapsulant; andforming a second redistribution structure on the encapsulant, the secondredistribution structure connected to the first redistribution structurethrough the conductive vias of the substrate.

In some embodiments, the method further includes: reflowing the firstconductive connectors and the second conductive connectors tosimultaneously bond the substrate and the integrated circuit die to thefirst redistribution structure. In some embodiments, the method furtherincludes: forming second openings in the encapsulant; and dispensingconductive paste in the second openings. In some embodiments of themethod, forming the second redistribution structure includes: forming abottom dielectric layer on the conductive paste and the encapsulant;planarizing the bottom dielectric layer; and forming a metallizationpattern extending along and through the bottom dielectric layer.

In an embodiment, a method includes: connecting a ring-shaped substrateto a first redistribution structure, the ring-shaped substrateincluding: a core having a cavity; first conductive vias extendingthrough the core; and conductive lines on the core, the conductive linesconnected to the first conductive vias; connecting a first integratedcircuit die to the first redistribution structure, the first integratedcircuit die disposed in the cavity of the ring-shaped substrate;encapsulating the ring-shaped substrate and the first integrated circuitdie with an encapsulant; and forming a second redistribution structureon the encapsulant, the second redistribution structure connected to thefirst redistribution structure through the first conductive vias and theconductive lines of the ring-shaped substrate.

In some embodiments, the method further includes: patterning openings inthe encapsulant exposing the conductive lines of the ring-shapedsubstrate; and filling the openings with a conductive paste to formsecond conductive vias, the second redistribution structure connected tothe second conductive vias.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A package comprising: a first redistributionstructure; a first integrated circuit die connected to the firstredistribution structure; a ring-shaped substrate surrounding the firstintegrated circuit die, the ring-shaped substrate connected to the firstredistribution structure, the ring-shaped substrate comprising a coreand conductive vias extending through the core; a encapsulantsurrounding the ring-shaped substrate and the first integrated circuitdie, the encapsulant extending through the ring-shaped substrate; firstconductive connectors extending through a first portion of theencapsulant, the first conductive connectors connecting the firstintegrated circuit die to the first redistribution structure; secondconductive connectors extending through a second portion of theencapsulant, the second conductive connectors connecting the ring-shapedsubstrate to the first redistribution structure; and a secondredistribution structure on the encapsulant, the second redistributionstructure connected to the first redistribution structure through theconductive vias of the ring-shaped substrate.
 2. The package of claim 1,wherein the second conductive connectors are a different size than thefirst conductive connectors.
 3. The package of claim 1 furthercomprising: an underfill disposed between the first integrated circuitdie and the first redistribution structure, the underfill surroundingthe first conductive connectors.
 4. The package of claim 3, wherein theunderfill further surrounds a first subset of the second conductiveconnectors without surrounding a second subset of the second conductiveconnectors.
 5. The package of claim 3, wherein the underfill furthersurrounds all of the second conductive connectors.
 6. The package ofclaim 1, wherein the first conductive connectors and the secondconductive connectors comprise copper pillars.
 7. The package of claim1, wherein the first conductive connectors and the second conductiveconnectors comprise solder connectors.
 8. The package of claim 1 furthercomprising: third conductive connectors extending through a thirdportion of the encapsulant, the third conductive connectors connectingthe ring-shaped substrate to the second redistribution structure.
 9. Thepackage of claim 8, wherein the third conductive connectors compriseconductive paste.
 10. The package of claim 8, wherein the secondredistribution structure comprises a bottom dielectric layer and a topdielectric layer, the bottom dielectric layer contacting the thirdconductive connectors and the encapsulant, a top surface of the bottomdielectric layer having a higher degree of planarity than a bottomsurface of the bottom dielectric layer, the bottom dielectric layerbeing thicker than the top dielectric layer.
 11. The package of claim 8,wherein the ring-shaped substrate further comprises: first conductivelines on a first side of the ring-shaped substrate, the first conductivelines connecting the conductive vias to the first redistributionstructure; a first solder resist on the first conductive lines, thefirst solder resist surrounding the second conductive connectors; secondconductive lines on a second side of the ring-shaped substrate, thesecond conductive lines connecting the conductive vias to the secondredistribution structure; and a second solder resist on the secondconductive lines, the second solder resist surrounding the thirdconductive connectors.
 12. The package of claim 1, wherein a firstheight of the first integrated circuit die is greater than or equal to asecond height of the ring-shaped substrate.
 13. The package of claim 1further comprising: a second integrated circuit die connected to thesecond redistribution structure; and a package substrate connected tothe first redistribution structure.
 14. The package of claim 1, whereinthe core comprises a pre-impregnated composite fiber.
 15. A packagecomprising: a first redistribution structure comprising under bumpmetallurgies (UBMs), a first subset of the UBMs disposed around a secondsubset of the UBMs, each of the first subset of the UBMs having a firstwidth, each of the second subset of the UBMs having a second width, thefirst width being greater than the second width; a ring-shaped substrateconnected to the first subset of the UBMs, the ring-shaped substratecomprising a core and conductive vias extending through the core; anintegrated circuit die connected to the second subset of the UBMs, theintegrated circuit die surrounded by the ring-shaped substrate; anencapsulant surrounding the integrated circuit die and the ring-shapedsubstrate; and a second redistribution structure on the encapsulant, thesecond redistribution structure comprising redistribution lines, theredistribution lines connected to the UBMs through the conductive viasof the ring-shaped substrate.
 16. The package of claim 15, wherein afirst portion of the encapsulant is disposed between the ring-shapedsubstrate and the first redistribution structure, and a second portionof the encapsulant is disposed between the ring-shaped substrate and thesecond redistribution structure, the package further comprising: firstconductive connectors extending through the first portion of theencapsulant, the UBMs of the first redistribution structure connected tothe conductive vias of the ring-shaped substrate through the firstconductive connectors; and second conductive connectors extendingthrough the second portion of the encapsulant, the redistribution linesof the second redistribution structure connected to the conductive viasof the ring-shaped substrate through the second conductive connectors.17. The package of claim 15, wherein the second redistribution structurefurther comprises dielectric layers, the redistribution lines disposedamong the dielectric layers, a lower dielectric layer of the dielectriclayers being thicker than an upper dielectric layer of the dielectriclayers, the lower dielectric layer being disposed closer to theencapsulant than the upper dielectric layer.
 18. A package comprising: afirst redistribution structure; a ring-shaped substrate connected to thefirst redistribution structure; an integrated circuit die extendingthrough a center portion of the ring-shaped substrate, the integratedcircuit die connected to the first redistribution structure; aencapsulant surrounding the integrated circuit die and the ring-shapedsubstrate, the encapsulant extending through the center portion of thering-shaped substrate, a portion of the encapsulant disposed between thering-shaped substrate and the first redistribution structure; and asecond redistribution structure on the encapsulant, the secondredistribution structure connected to the first redistribution structurethrough the ring-shaped substrate.
 19. The package of claim 18 furthercomprising: first reflowable connectors connecting the ring-shapedsubstrate to the first redistribution structure; and second reflowableconnectors connecting the integrated circuit die to the firstredistribution structure, the second reflowable connectors being smallerthan the first reflowable connectors.
 20. The package of claim 18,wherein the second redistribution structure further comprises dielectriclayers, the dielectric layers including a lower dielectric layer and anupper dielectric layer, the lower dielectric layer being disposed closerto the encapsulant than the upper dielectric layer, a top surface of thelower dielectric layer having a higher degree of planarity than a bottomsurface of the lower dielectric layer.